Applications Of Derivatives Question 199

Question: If $ y={x^{{x^{x……\infty }}}} $ , then $ \frac{dy}{dx}= $

[UPSEAT 2004; DCE 2000]

Options:

A) $ \frac{y^{2}}{x(1+y\log x)} $

B) $ \frac{y^{2}}{x(1-y\log x)} $

C) $ \frac{y}{x(1+y\log x)} $

D) $ \frac{y}{x(1-y\log x)} $

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Answer:

Correct Answer: B

Solution:

$ y={x^{{x^{x…….\infty }}}} $

therefore $ y=x^{y} $

therefore $ \log y=y\log x $

Therefore, on differentiating $ \frac{dy}{dx}=\frac{y^{2}}{x(1-y\log x)} $ .